Well-defined crystallites autoclaved from the nitrate/NH{sub 4}OH reaction system as the precursor for (Y,Eu){sub 2}O{sub 3} red phosphor: Crystallization mechanism, phase and morphology control, and luminescent property
- Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China)
- World Premier International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan)
- College of Chemistry, Beijing Normal University, Beijing 100875 (China)
- Advanced Materials Processing Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan)
Autoclaving the rare-earth nitrate/NH{sub 4}OH reaction system under the mild conditions of 120-200 Degree-Sign C and pH 6-13 have yielded four types of well-crystallized compounds with their distinctive crystal shapes, including Ln{sub 2}(OH){sub 5}NO{sub 3}{center_dot}nH{sub 2}O (Ln=Y and Eu) layered rare-earth hydroxide (hexagonal platelets), Ln{sub 4}O(OH){sub 9}NO{sub 3} oxy-hydroxyl nitrate (hexagonal prisms and microwires), Ln(OH){sub 2.94}(NO{sub 3}){sub 0.06}{center_dot}nH{sub 2}O hydroxyl nitrate (square nanoplates), and Ln(OH){sub 3} hydroxide (spindle-shaped microrods). The occurrence domains of the compounds are defined. Ammonium nitrate (NH{sub 4}NO{sub 3}) as a mineralizer effectively widens the formation domains of the NO{sub 3}{sup -} containing compounds while leads to larger crystals at the same time (up to 0.3 mm). Crystallization mechanisms of the compounds and the effects of NH{sub 4}NO{sub 3} were discussed. Optical properties (PLE/PL) of the four phases were characterized in detail and were interpreted from the different site symmetries of Eu{sup 3+}. The compounds convert to cubic-structured (Y{sub 0.95}Eu{sub 0.05}){sub 2}O{sub 3} by annealing at 600 Degree-Sign C while retaining their original crystal morphologies. The resultant phosphor oxides of diverse particle shapes exhibit differing optical properties, in terms of luminescent intensity, asymmetry factor of luminescence and fluorescence lifetime, and the underlying mechanism was discussed. - Graphical abstract: Well-defined crystallites of the various phases have been autoclaved from the nitrate/NH{sub 4}OH reaction system. Crystallization mechanisms of the compounds and the effects of NH{sub 4}NO{sub 3} were discussed. Highlights: Black-Right-Pointing-Pointer Well-defined crystallites of four phases have been hydrothermally synthesized. Black-Right-Pointing-Pointer The occurrence domains of the compounds are defined. Black-Right-Pointing-Pointer Crystallization mechanisms and the effects of NH{sub 4}NO{sub 3} mineralizer are discussed. Black-Right-Pointing-Pointer PL properties of the compounds and their calcination products are studied.
- OSTI ID:
- 22131127
- Journal Information:
- Journal of Solid State Chemistry, Vol. 192; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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